Unwinged Pegasus

Via the invariably spectacular Ptak Science Books blog, a quick peek back at the brief heyday of airborne horses:

"Sep 1850 English Aeronaut Gale on horseback suffocated Bordeaux". Is this the first man-on-horseback-in-flight death? And death by suffocation? (?) I'm not so sure that the ascent records for 1850 would've made allowance for running out of oxygen at high altitudes–if not, then how did this man suffocate? According to the Dictionary of National Biography, which, somehow...